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Do you have to eat 800-1200 calories a day in order to lose weight?

Image result for ultra low calorie diet

Personal trainers have nightmares sometimes – many of which are recurring fears. There are 2 most popular ones:

  1. Clients that lie in their food journals
  2. Clients that are scared to eat anything at all

The first category are the ones who are secret bingers or maybe just accomplished liars. They don’t want to let the trainer down and sometimes they’re scared of what the trainer will say. The second category are often those which confuse feeling full with feeling fat.

When you eat a large meal – particularly one heavy in carbohydrates – you naturally retain water and your stomach expands because it’s FULL. Literally full. This doesn’t mean you’re instantly fatter than you were before. Granted, your weight may actually go up as much as 5-10 lbs after a heavy meal and reasonable amounts of fluid, but once your body has had time to process and digest the food, you’ll often find you’re not any heavier than you were.

Of course, if you keep eating more food than is required for your daily activity levels, this will result in weight gain.

So it begs the question: Just how many calories do you need to eat in order to lose weight? Is it as low as 800 in some extreme cases, or can it be done as high as 2500 calories per day?

To answer these questions let’s take a look at the factors at play when determining how many calories one needs to eat in order to achieve their goals.

Factor One – Your BMR

BMR stands for Basal-Metabolic-Rate. In layman’s terms this is the amount of energy you require, or your body requires, to support daily essential functions. This is the amount of calories needed to support the organs and keep all body processes working. Now you may or may not know, but your BMR is assuming you aren’t doing anything other than laying still (vegetating).

Even if you’re the best example of a couch potato I can find, I’m willing to bet you do more in a day than spend 24 hours laying in one position.

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(Image credit:

Factor Two – Your Activity Level

Someone who works as a removal man and plays American football 4 nights per week after work, is going to need a vast amount of calories over their BMR than someone who is jobless and spends all day watching television. But you knew that already.

Where the problems arise are the miscalculations of just how many calories an active person truly needs. In my most recent post reviewing Emmet Louis’ Modern methods of mobility seminar, I included that he said this was a classic problem; eating low calorie diets while exercising all the time.

Factor Three – The Quality Of The Food You Eat

The composition of the food you eat determines the amount of energy required to process the food itself. Two types of food require the most energy to break down. They are A) Protein and B) Vegetables. In fact many vegetables require more energy to break down than what they actually contain, coupled with their rich micronutrient profile and satiation properties, makes them an amazing choice for fat loss.

While you certainly can find your weight loss range in terms of daily calories and fill them calories with foods considered ‘junk’ such as takeaways, pop tarts, ice cream and chips….such a diet will leave you far less satiated and much more undernourished than a whole foods diet rich in vegetables, protein, fruits and natural carbohydrates.

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(Image credit – these do more for your body than processed foods ever will

Factor Four – Your Personal Details; Age, Weight, Sex & Activity Level

No 2 people are the same. Individual variances govern how much energy we require on a daily basis, even just to exist – not factoring in variances in people’s amount of movement. We get those lucky people who have Lamborghini-esque metabolisms (bastards) that can eat copious amounts of food and not gain any bodyfat…..and we get those who find putting on weight rather easy.

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NOTE: Just because I acknowledge some people have slower metabolisms, I certainly don’t buy into some people finding it ‘impossible’ to lose weight; those who have “tried everything”. Try harder or hire a good personal trainer.

Despite individual differences in metabolic efficiency there are other pivotal elements involved in how many calories one may need. The amount of muscle you have is one. Muscle is very metabolically expensive; it costs calories to keep muscle tissue. This is why men generally have faster metabolisms than women. Sorry girls!

Finding The BMR & Figuring Out How To Set Calories For Weight Loss

Instead of bore you with the exact equations for calculating BMR, I will leave a link to a Google search result with all the possible calculators out there:


I will use my stats as an example. I am male, 25 years old, around 80 kg/175 lbs, 5’11” tall. My BMR is 1,888 calories per day! As we’ve already established, I will need considerably more than this number. I’m not a couch potato, believe it or not!

For the sake of simplicity, I will use a well known formula to roughly figure out my calorie needs.

Harris Benedict Formula
To determine your total daily calorie needs, multiply your BMR by the appropriate activity factor, as follows:

  1. If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.2
  2. If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.375
  3. If you are moderately active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.55
  4. If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.725
  5. If you are extra active (very hard exercise/sports & physical job or 2x training) : Calorie-Calculation = BMR x 1.9

It can be surprisingly difficult to categorise yourself with any of the above accurately. And as you can probably imagine, I’ve fell victim to a massive case of over-thinking with this stuff before……..

“What exactly is considered ‘hard exercise’?

“I wonder if anyone has released any way of knowing, definitively, what category you fall into……..”

The above are a waste of time and mental energy. Just be honest and select the category that you genuinely feel applies most. For me it’s probably the moderately active one or between that and very active. If you really can’t decide between 2, simply use an equation halfway.

I’m somewhere between moderately active and very active. Therefore I’m going to use a value between 1.55 and 1.725.

That value is 1.63. 1.63 x 1,888 = 3,077 calories. We will round that up to 3,100 for simplicity’s sake. And this is just what I’d need for maintenance, to account for daily energy expenditure.

Now we have numbers to work with! In order for fat loss to occur, an energy deficit is a must. Just how big the deficit is really depends on who you talk to, but for me I like anywhere from 250-500 calories. If the deficit is greater than 500 calories I find it’s too aggressive unless it’s been gradually built upto.

A deficit of less than 250 calories per day would still get you leaner but it would take longer than necessary, in my humble opinion.

Doing the mathematics we get a general calorie range in order to initiate fat loss based on my stats:

3,077 – 250 = 2,827 (rounded up for simplicity = 2,850)

3,077 – 500 = 2,577 (rounded up for simplicity = 2,600)

Depending on how fast I wanted to lose fat, I’d select one of these 2 figures and aim to stick to them day in, day out. If anything, I’d endorse using the higher end of the 2 as this gives more room to adapt to the new energy intake. Once your body adapts to the 250 daily deficit, increase the deficit to 500 and you’ll continue to make progress.

It isn’t as complex as they’d like you to believe

Hopefully this has explained why these low calorie diets and even fads/cons like diet pills, fat burners, secret fat loss diets and even good old starvation do not work long term; your body simply needs calories to function, let alone function optimally while becoming fitter and stronger.

Use the equations yourself and share them with anyone you know that may benefit from them. Regardless of your background, gender or age, you’ll find the numbers are probably higher than your favourite guru or local magazine suggested. And for those worrying, I’ve seen this to be the case with so many clients in the real world; as soon as they eat a bit more, the results start coming.

Cutting calories too hard doesn’t work. It sets up classic rebound habits…….and who wants that? Nobody that reads my content.

Further reading and resources:

Simplifying calorie & macro tracking

Carbs and fat gain: What 2 years of experimentation taught me

For any more info or questions, leave a comment or for personal training/coaching enquiries email me at:

Thanks for reading.

JR @ Straight-Talking-Fitness View All

The 'brains' behind StraightTalkingFitness, a site all about discovery that leads to strength in all formats; fitness, mental, emotional and spiritual. Everything starts from within and projects outwards. Master the body, master anything and everything.

50 thoughts on “Do you have to eat 800-1200 calories a day in order to lose weight? Leave a comment

  1. You really don’t. In my view, it centers around workload. The body may be made in the kitchen, but you still have to put in the work to see results.

      • Lotta people think you have to carb count, all that jazz. It’s not one size fits all. Every body is different. What you said is true, especially if you didn’t win the genetic lottery. Hopefully the fitness industry starts realizing this instead of continuing to shove this one size fits all ideology down people’s throats.

      • Absolutely. I’ve been really lean on a very high carb diet and felt great. That goes against a lot of what the mass media preach/promote. It’s all one big experiment, I believe. But I think it’s important to challenge the norm…….it really is.

      • I catch hell for challenging the narrative the fitness industry puts out. You literally have to make sure you know who you are- in every sense to have success in your fitness goals. The industry itself maintains their interests and the public swallows it hook, line and​ sinker.

  2. If anyone really following this kind of diet you are actually harming your body. The right way to go for it is to deplete your energy reserve and that is carbs stored as fat in your body so you need to cut your carbs and for an average persons you won’t be going less than 1700 calories and i don’t believe that you can lose fat percentage without controlling your carbs or other way increasing your intensity of workout by keeping carbs same.

    • There are many people eating this kind of diet, I’ve seen them quite often. It’s asinine really. You’re right, for those training hard and properly, 1700 calories is still on the very low side – and I’d much rather have them get the fat loss effect from the training than a restrictive diet. Thanks for leaving a comment.

  3. So interesting. I took your advice and calculated my BMR and how many calories I need to eat to lose weight. It’s a lot more than the fitness apps I’ve been using would have me believe!

    • Many fitness apps and even gurus will claim you need ultimate restriction can’t eat more than a plate of salad per day but it’s really not the case at all. I’ve seen fat loss occur at ‘very high’ calorie intakes. You just need to be smart with it.

  4. Wow. I’m really guilty on trying to eat very less to the point that I neglect the nutrition value. Thanks for your article! I’m new in blogging and I hope to inspire people as well!

    • Most people over-restrict – quite grossly in some cases and then wonder why they feel bad, hate the gym and want to get straight off their ‘diet’. The slower approach works so much better long term.

      Welcome to the blogging world! Keep putting out good content.

  5. Hi
    Nice post! I’ve made a post about calories so if you have time and will please go and check it out! If you like it pls follow me, I follow you.
    Thank you! 😀

  6. Ahhh, reminds me of school–lol. We learned these calculations and it was fascinating!

    Before I really got into learning the actual calculations, I would use online IIFYM calculators to see how many calories I should be eating, and boy did those number f*&% me over. I had such anxiety if I “went over my calories” for the day and later realized that my numbers were way too low for me and my activity level. Since then I’ve just stuck to intuitive, clean eating and that seems to be working 🙂

    No more rice cakes with almond butter–thank God. And MyFitnessPal. Haha. Great post!

      • Yeah, I did do IIFYM for about 2 months, trying to figure out my actual calories needed, but I always felt miserable because they were too low (a dietitian put my sister on the same amount of calories as me and that’s when I realized it was way too low) but I do like the idea of IIFYM, I’ll probably do it again in the future but for now I’m just making sure I’m getting to the right amount of protein. Now that I actually know the calculations I probably wouldn’t have a problem.

      • The figuring out part is the hardest generally and then confirming that said foods contain the calories that they’re supposed to. I agree the freedom of an IIFYM approach helps with not feeling deprived, but I would always edge towards more wholefoods in the diet than dirtier foods. But looseness in my own diet hasn’t done me that much harm really. Being overly anal gets you nowhere, I’ve learnt.

  7. I loved this! I really enjoyed reading this and I learned alot! I loved the food chart on which foods can help boost your metabolism. Side note: Grape fruit with a little brown sugar on it heated up (cut in half) in the microwave is so good! It’s kind of like a little dessert without being terribly unhealthy for you.

    • Thanks very much, glad you got something from it! I’ve not heard that little grapefruit trick before, I’ll have to give it a go. I always use fruit as a sugar craving killer/snack filler. Grapefruit is calorie negative I believe too?

  8. I’m in complete agreement. I think people who eat minimal calories aren’t helping themselves at all. You need a well-balanced diet and exercise in order to lose weight. People are so afraid of fat that they avoid it. When really, your body needs fat to function … focus on your healthy fats: avo, nuts, butter. I really enjoyed reading this. Check out my blog for fitness and product reviews 🙂

    • Thanks Lianna, pleased you enjoyed it. Yeah, I still hear the fat phobics often, thinking eggs lead to heart disease and coconut oil is terrible for you. I think gradually people are starting to realise though. It just takes ages for myths and hype to die. I’ve seen your site and you’ve got loads of good reviews! Any new reviews on the agenda?

      • I’m still a coconut oil believer! 🙂 Thanks for visiting my site. I’ve got a few reviews coming up. You’ll have to subscribe to read them.

  9. Love this, sometimes I also find that people over think it. I also recently published a post on the different body-types in relation to fat burn/muscle gain/caloric needs…would welcome some feedback!

  10. I really think that the 1200 calorie myth does more harm than good. Sure for a few (probably short) people it might make sense but it can do a lot of harm too. It can lead to binges due to hunger, disordered eating and sometimes a full fledged eating disorder. The most important part of loosing weight is keeping it off. It’s a lifestyle change too right? Why not just eat the calories for your goal weight and get there a little slower?

    • I agree 100%. If you’re active enough there’s no way you should need to restrict calories that low in order to lose body fat. The other thing you see with crash dieting is people not having the energy to train properly and still refusing to eat more, when told. It’s because the process is slow people think they need to force it or can speed it up. And, as you rightly say, this is dangerous.

      Thanks very much for sharing your take on it and leaving a comment 🙂

  11. Great article this i found very informative.. food intake is something I have struggled with but my pt has given me a nutrition plan and it seems to be intake is about being clever and listening to your body in my view 🙂

      • Tell me about from my most recent blog post you will see i have now given up alc all together..its time for change. The plan is a high protein diet- cutting fat whilst keeping muscle. Im trying to speed my metabolism up 🐯

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